The Age of Discovery of Elements Essay

880 Words 4 Pages
The Age of Discovery of Elements "The nineteenth century was the golden age for the discovery of
elements. Scientists began to look for patterns of behaviour between
elements."*1 Johann Döbereiner, a German chemist, was the first to
attempt to categorise the elements. He used their atomic weights,
which we now know as atomic masses.

In 1863, John Newlands, produced something that he called the 'Law of
Octaves'. He used this to produce his own version of the periodic
table, but Newlands came across some problems. "After about 20
elements his table became ragged,"*2 Newlands had left no gaps for
undiscovered elements and even
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"Every element has it own characteristic set of lines. A
new line (or lines) in a spectrum meant a new element."*6

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He called it Gallium, this new element had very similar properties to
Mendeleev's predicted element 'eka-aluminium'; this therefore
supported his idea of the Periodic table hugely.

Table 1, comparing Mendeleev's prediction with the properties of
element 31, gallium. *7




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Gallium has some very unusual properties, some which suggest that it
is a metal and some that imply it is a non-metal.

Its physical properties, a melting point of 29.78°C (which is almost
UK room temperature) making it a liquid metal along with Mercury and
Caesium. It also has an extremely high boiling point, 2403°C; together
with its low boiling point gallium has the 'widest liquid range' of
any element discovered so far. Gallium is also denser as a liquid than
as a solid, as is water.

Word count: 190




Gallium's chemical properties include, dissolving in acid and alkalis,
evolving hydrogen. Aluminium and…

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